The change of left ventricular function and mechanical dispersion in patients with hypertrophic cardiomyopathy :a study with exercise stress echocardiography / 中华超声影像学杂志

ABSTRACT

To investigate the association between the change of left ventricular ( LV ) function and mechanical dispersion ( MD ) and exercise capacity in patients with hypertrophic cardiomyopathy ( HCM ) by exercise stress echocardiography . Methods Sixty‐five HCM patients [ 40 cases of hypertrophic non‐obstructive cardiomyopathy ( HNCM ) , 25 cases of hypertrophic obstructive cardiomyopathy ( HOCM ) ] and 25 control subjects were recruited .LV function ,MD and exercise capacity were evaluated by two‐dimensional speckle‐tracking imaging and echocardiography at rest and during exercise ,and the following parameters of LV function were recorded : LV global longitudinal strain ( LVGLS) ,MD ,early diastolic strain rate ( Sre) ,the ratio of peak early diastolic mitral inflow and annulus velocity ( E/e′) ,LV outflow tract gradient ( LVO TG) ; LV functional reserve was assessed by ΔLVGLS and ΔSRe ; exercise capacity was evaluated by metabolic equivalents ( M ET s ) . T he association between the change of LV function and MD and exercise capacity was investigated . Results ①Compared with normal controls ,LVO TG ,E/e′ and MD increased ,and LVGLS ,Sre , ΔLVGLS , ΔSRe and M ET s decreased in HNCM patients at rest and during exercise ( all P ＜ 0 .05 ) . ② LVO TG , E/e′ and MD were further increased ,LVLGS ,Sre ,ΔSRe and M Ets were further reduced in HOCM patients compared with HNCM patients ( all P ＜ 0 .05 ) . ③LVGLS and MD measured at peak exercise were associated with M ET s ( r ＝－0 .68 , P ＜ 0 .001 ; r ＝ －0 .43 , P ＜ 0 .001 ) . ④ ROC curve analysis showed LVGLS had a better predictive value for exercise intolerance in HCM patients ,followed by E/e′ and MD . Conclusions LV function and mechanic reserve are reduced but MD is increased in HCM patients ,especially in HOCM patients . Exercise capacity is associated with LV function and MD ,w hich can predict the reduced exercise capacity in HCM patients .